Latching device.



H. G. BAXTER.

LATCHING DEVICE.

APPLICATION FILED JUNE 9, 1914.

1,229,703. Patented J une 12, 1917. 1 /3 WITNESSES: INVENTOR Harold Godfrey Baxte r.

BY 2 E ATTORNEY UNITED STATES PATENT OFFICE. I

HAROLD G. BAXTEB, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR I'O WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

LATCHING DEVICE.

Specification of Letters Patent.

Patented June 12, 1917.

To all whom it may concern:

Be it known that I, HAROLD GODFREY BAX ran, a subject of the Kin of Great Britain, and a resident of Wilkins urg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Latching Devices, of which the following is a specification.

My invention relates to latching devices, and particularly to latching devices for electrical switches.

One object of my invention is to provide a latching device, of the above indicated type, which will prevent its knife-blade member from becoming accidentally disengaged from its cooperating stationary contact members.

Another object of my invention is to pro vide a hook member having means for operating a latching device and means for preventing any accidental removal of the same from the latching device.

. I provide a latching device for preventing the disengagement of the movable and stationary members of a knifeblade switch if, for any reason, there should be a tendency for the same to become accidentally disengaged. This frequency occurs when excessive short circuits or other disturbances affeet the bus-bars to which the contact members are connected. Disturbances on the bus-bars will usually cause the same to buckle, and thus allow the cooperating members of a knife-blade switch to become disengaged.

Fi re 1 of the accompanying drawings is a si e elevational view of a knife-blade switch provided with a latch member embodying my invention, and Fig. 2 is a top lan view of the knife-blade switch shown in Fig. 1.

A knife-blade member 1 is pivotally attached to a stationary terminal member 2 and enga es stationary contact members 3 and 4, su stantially as shown in the drawing. A latching device 5 is attached to the upper ortion of the knife-blade member 1 by a p urality of bolts 6. The latching device 5 comprises a main casting 5 having a substantially annular projecting member 7, a rotatable member 8, a bolt member 9 and a sprin 10. The member 8 is rotatably mounte upon the bolt 9 and has its lower face formed into a cam to cooperate with a cam face on the main portion of the casting 5'. The spring 10 is disposed around the bolt 9 and between the casting 5 and a member 11. Each of the stationary contact members 3 and 4 is provided with a notch 12 for receiving the member 11. The bolt 9 is retained in operative relation to the latching devices 5 by a washer 13 and a dowel pin 14. An operating member 15, comprising a handle 16 and a hook member 17 having an annular groove 18, is provided for operating the device, as hereinafter set forth.

Assuming that the device is in the position shown in the drawing and that it is desired to disengage the knife-blade member 1 from the contact members 3 and 4, my invention operates as follows:

The hook member 17 is inserted in the annular projecting member 7 causing the member 8 to rotate and the bolt 9 to move in a longitudinal direction against the action of the spring 10. The groove 18 in the member 17 is provided for engaging the annular projecting member 7, substantially as shown in Fig. 2 of the drawing. The longitudinal movement of the bolt 9 disengages the member 11 from the notches 12 and allows the knife-blade member 1 to be disengaged from the stationary contact members 3 and 4: when the operating member 15 is drawn out wardly.

To close the switch, the' member 15 is moved inwardly until the knife-blade member 1 reaches the limit of its travel. The spring 10 presses down upon the member 11, after the withdrawal of the member 15, and causes the member 8 to rotate to its initial position, as shown by the full lines in Fig. 2 of the drawing. The cam faces of the mem-, ber 8 and thecasting 5 are so proportioned that, when the member 8 is rotated through an angle of substantially 45, it will raise the member 11 out of engagement with the notch 12.

The annular groove 18 is so proportioned that it engages the annular projecting member 7, thereby limiting the rotative movement of the member 8. The groove 18 prevents the hook member 15 from becoming disengaged from the knife blade member when the same'is being operated.

My invention is not limited to the particular construction illustrated, but is capable of various modifications within the scope of the appended claims.

I claim as my invention:

1. The combination with a stationary and a movable member, of means for locking said members in engagement, a relatively stationary .ca-m member mounted on the movable member, and a rotatable cam member operatively connected to the locking means and adapted to cooperate with the stationary cam memberto release the said locking means when the rotatable cam member is turned.

2. In a knifeblade switch, the combination with cooperating contact members, of an eye member attached to the movable contact member, a locking means for engaging the stationary contact member when the switch is closed, a relatively stationary cam member mounted on the movable contact member, a, rotatable cam member adapted to cooperate with the stationary cam member to actuate the locking means when it is turned, and a hook member adapted to actuate the rotatable cam member when it is inserted in the e e mem er.

3. n a knife-blade switch, the combination with stationary contact members, and a cooperating lmife-blade member, of an eye member and a stationary cam member mounted on the knife-blade member, a bolt for normally engaging said stationary contact member when the switch is closed, a ro-- tatable cam. member adapted to cooperate with the stationary cam member to release the bolt, and an operating hook member adapted to actuate the rotatable cam memher when it is inserted in the eye member.

4. A latching device for a knife-blade switch comprising a bolt carried by the movable member of the switch and adapted to engage the stationary member, a relatively stationary cam member mounted on the movable member of the switch, and a rotatable cam member operatively connected to the bolt and adapted to cooperate with the stationary cam member to disengage the bolt from the stationar member of the switch when the rotatab e cam member is rotated.

5. In a knife-blade switch, the combination with stationary and movable contact members, of a bolt for locking the contact members in engagement, a relatively stationary cam member mounted on the movable contact member, and a rotatable cam member operatively connected to the bolt and adapted to cooperate with the stationary cam Ito release the said bolt when the rotatable cam member is rotated.

In testimony whereof, I have hereunto subscribed my name this 29th day of May, 1914.

HAROLD G. BAXTER. 

